In the field of magnetic heads to be mounted on a magnetic recording apparatus such as a hard disk drive (HDD), recently, the recording method is being shifted from longitudinal recording to perpendicular recording in order to improve the recording density with respect to a magnetic recording medium such as a hard disk. The perpendicular recording method achieves high linear recording density and also has an advantage that the recording medium after recording becomes highly resistant to heat fluctuation.
A perpendicular recording magnetic head is provided with a coil film for generating a magnetic flux and a magnetic pole film for guiding the magnetic flux to a recording medium. The magnetic pole film is constituted by a plated film formed by electroplating on an electrode film 13 intended to function as a seed film.
In the meantime, improvement in recording capacity of a hard disk drive (HDD) requires not only to increase the track density by reducing the magnetic pole film width at the magnetic head but also to improve the recording resolution by increasing the coercive force of the medium.
In order to assure sufficient overwrite characteristic (OW) with respect to a medium of a high coercive force, the magnetic head must have a main magnetic pole film with a high saturation magnetic flux density. In the prior art, accordingly, a plated film forming a main portion of the main magnetic pole film is made of a high saturation magnetic flux density material, such as a FeCo material, a CoNiFe ternary alloy film, and a high saturation magnetic flux density material such as Fe, and FeN, and the electrode film intended to function as a seed film is also made of a high saturation magnetic flux density material. For example, Japanese Unexamined Patent Application Publication No. 2006-253252 discloses a main magnetic pole in which a FeCoNi plated film is formed on a FeCoNi electrode film. It describes that the saturation magnetic flux density (Bs) of the main magnetic pole reaches 2.4 T.
In the perpendicular recording magnetic head, however, merely increasing the saturation magnetic flux density is not sufficient, and it is also necessary to avoid the “pole erase” phenomenon in which a signal recorded on a magnetic recording medium by the main magnetic pole film becomes erased when recording is not performed.
In the perpendicular recording magnetic head, the main magnetic pole film for recording has its hard axis directed along an air bearing surface to perform recording in magnetization rotation mode. That is, residual magnetization along the air bearing surface is minimized to prevent an excess magnetic flux from being emitted when recording is not performed, thereby avoiding the pole erase. In order to assure this function, the coercive force Hc of the main magnetic pole film has to be kept low.
As means for avoiding the pole erase, Japanese Unexamined Patent Application Publication No. 2006-269690 discloses a technique of achieving not only a high saturation magnetic flux density Bs but also a low coercive force Hc by orienting the crystal of a FeCo alloy plated film in (110) with the FeCo alloy plated film formed on a non-magnetic conductive layer containing one or more elements selected from Ru, Rh, Ir, Cr, Cu, Au, Ag, Pt and Pd.
In order to deal with the improvement in recording capacity of the hard disk drive (HDD), on the other hand, it is required to increase the track density by reducing the main magnetic pole film width at the magnetic head, but since the main magnetic pole film width decreases with increasing the recording density of the magnetic recording, it is significantly important to control the width with high accuracy from the viewpoint of improving the yield of the magnetic head.
In the prior art, however, since the FeCo alloy plated film, which constitutes the main magnetic pole film, is formed on a planar non-magnetic conductive film, as disclosed in Japanese Unexamined Patent Application Publication No. 2006-269690, it has been difficult to control the main magnetic pole film width more accurately than the patterning accuracy of the photolithography technique or the like.